1. Field of the Invention
The present invention relates to a screen printer used for such as printing a resist in case of printing or etching during the process of electrically wiring on a board. The invention relates to, in particular, a screen printer used for a screen printing method in which gas pressure between a screen mesh and a work is made higher than gas pressure at a side of printing using a squeegee of the screen mesh.
2. Description of the Related Art
FIG. 9 shows a conventional technique of a screen printer.
In FIG. 9, a reference numeral 1 shows a screen, 3 shows a squeegee, 5 shows a screen frame, 6 shows a work, 8 shows ink, and 10 shows a table.
According to the conventional screen printing, as shown in FIG. 9, a clearance of several mm is placed between the screen 1 and the work 6 which is a board to be processed. After supplied to the screen 1, the ink is spread by the squeeze 3 toward the user""s side, while the squeegee 3 presses the screen 1 downward with stretching the screen 1 so that the screen 1 adheres to the work 6 of the board, and then the screen 1 is removed from the work 6 of the board due to the tension of the screen. Printing is thus performed on the work 6 of the board.
As for the clearance between the screen 1 and the work 6, for example, the clearance of 2-6 mm is placed when the internal size of the screen frame is 500 mm. Further, as greater the internal size of the screen frame becomes; such as 1,000 mm, 2,500 mm, and more, it is also required to make the clearance bigger. There are some problems in the conventional printing method, in which the clearance, for example, of 2-6 mm is placed between the screen 1 and the work 6. As the screen 1 is stretched for printing, the printing accuracy is not sufficient. It is required to make the screen 1 larger than the work of the board, which increases the cost of the screen 1. Moreover, as the screen 1 is stretched for printing, the screen 1 does not last long.
The present invention aims to improve the printing accuracy.
Further, the invention aims to make the screen smaller compared with the conventional processing pattern, which enables to reduce the cost of the screen.
Further, the invention aims to lengthen the life of the screen.
According to the present invention, a screen printer for performing screen printing using a screen plate includes:
a table placed facing the screen plate;
a screen sealing unit for nearly sealing a space between the screen plate and the table, and
the screen sealing unit includes a screen receiving unit placed facing the screen plate and
a sealing aid unit placed facing the table.
The screen printer of the invention further includes an elastic body, and the sealing aid unit is placed slidable along the table and is pressed to the screen receiving unit by the table through the elastic body.
In the screen printer of the invention, the screen sealing unit further includes a packing material, and
the screen receiving unit has a projection part circularly formed, and the projection part is pressed to the sealing aid unit through the packing material.
According to another aspect of the invention, a screen printer for performing screen printing using a screen plate and a squeegee, includes a table placed facing the screen plate and having an opening,
the screen printer performs screen printing on a work placed on the table using the screen plate and the squeegee, and supplies gas having a higher pressure than a pressure of atmosphere of a side of the screen plate opposite to the table, and
the opening supplies gas to the screen plate, and is formed outside the work placed on the table and at least at one of fore and rear in a printing direction of the squeegee as a long slot which is long in an approximately right angle direction against the printing direction of the squeegee.
The screen printer of the invention further includes:
a regulator for controlling a pressure of the gas; and
an opening valve for releasing a pressure which is increased by the gas supplied into the space between the screen plate and the table.
In the screen printer of the invention, the screen printer performs screen printing on a work using a squeegee, and
the table includes a supply hole which is formed at least at one of fore and rear of the table in a printing direction of the squeegee and supplies gas toward the screen plate with an angle slanted to the work.
In the screen printer of the invention, the supply hole formed at least at one of sides of the table in a printing direction of the squeegee and supplies gas to the screen plate.
The screen printer of the invention further includes:
a filter for filtering the gas supplied to the space which is nearly sealed between the screen plate and the table; and
a compressed gas generating unit for increasing a pressure of the gas filtered and supplying the gas of which the pressure is increased to the supply hole.
In the screen printer of the invention, the screen printer performs screen printing using ink including solvent, and the gas includes the solvent.
The screen printer of the invention further includes a supply hole for supplying gas into a space which is nearly sealed by the screen plate, the table, and the screen sealing unit.